Escherichia sp.

General: Includes five species, dominated by E. coli in terms of both frequency and pathogenicity, a species which is further subdivided into numerous serotypes. Normal gastrointestinal flora of humans and animals. May spread by fecal-oral, contaminated food, water, milk, or undercooked beef. May cause both GI and extra-GI (esp. urinary, blood, wound, and nosocomial respiratory) infections.

Resistance:

Growth characteristics: Gray, smooth, usually beta-hemolytic colonies on blood agar which appear within 12-18hrs aerobically at 35C. Most strains ferment lactose rapidly.

Common pathogens:

• Escherichia coli
  • Enteroaggregative
  • Enterohemorrhagic
  • Enteroinvasive
  • Enteropathogenic
  • Enterotoxigenic